This application claims the benefit of Japanese Application No. 2001-325811 filed Oct. 24, 2001.
The present invention relates to an RF (radio frequency) coil and a magnetic resonance imaging apparatus, and particularly to an RF coil disposed proximate to and surrounding a subject to be imaged, and a magnetic resonance imaging apparatus employing such an RF coil.
In a magnetic resonance imaging apparatus, an RF coil is disposed proximate to and surrounding a subject to be imaged so that magnetic resonance signals are measured as close to a region to be imaged as possible to improve the SNR (signal-to-noise ratio) of the signals.
A representative example of such an RF coil is a cylindrical RF coil for inserting the subject""s head, i.e., a head coil. In a magnetic resonance imaging apparatus employing a magnetic field of a strength as low as 0.2 T or 0.5 T, for example, such an RF coil is also employed for imaging the subject""s trunk. In this case, the RF coil is constructed to be developable. The developed RF coil is placed on an imaging table, the subject is rested over the developed RF coil, and finally the developed portion of the RF coil is closed to form the cylinder.
Since the RF coil having the aforementioned configuration hangs down on the right and left sides of the subject to be imaged due to gravity in its developed condition, an operator lifts the hanging portions up by the hands to wrap the subject to be imaged from both sides.
Generally, the work is done with the operator on one side of the subject, and he/she must stretch his/her hand over the subject to the opposite side to lift the hanging portion. At that time, the proximal portion that lies near at hand is often lifted up by one hand, and therefore, stress is concentrated at the proximal portion, possibly resulting in breakage over the repeated work.
It is therefore an object of the present invention to provide an RF coil that prevents a troublesome force from arising when the hanging portion is lifted up, and a magnetic resonance imaging apparatus comprising such an RF coil. Another object of the present invention is to provide an RF coil that offers good workability for the lifting up of the hanging portion, and a magnetic resonance imaging apparatus comprising such an RF coil.
(1) The present invention, in one aspect thereof for solving the aforementioned problem, is an RF coil characterized in comprising: a base member; a pair of flexible substrates each having an electric circuit for the RF coil, one end of each flexible substrate being attached to a lateral side of said base member, the other ends of the flexible substrates being coupled to each other via a coupling member to form a cylinder; a shape defining member attached to a side of said pair of flexible substrates that corresponds to an inner side of said cylinder, for defining a curved shape of said pair of flexible substrates when said cylinder is formed; and a pair of handhold members each provided along a side that corresponds to an inner side of said shape defining member in said cylinder, each handhold member extending from one end to the other end of one of said pair of flexible substrates.
(2) The present invention, in another aspect thereof for solving the aforementioned problem, is an RF coil characterized in comprising: a base member; a pair of flexible substrates each having an electric circuit for the RF coil, one end of each flexible substrate being attached to a lateral side of said base member, the other ends of the flexible substrates being coupled to each other via a coupling member to form a cylinder; a shape defining member attached to a side of said pair of flexible substrates that corresponds to an inner side of said cylinder, for defining a curved shape of said pair of flexible substrates when said cylinder is formed; a sheet member provided along a side that corresponds to an inner side of said shape defining member in said cylinder, extending from one end to the other end of each of said pair of flexible substrates; and a pair of handhold members each provided along a side that corresponds to an inner side of said sheet member in said cylinder, each handhold member extending from one end to the other end of one of said pair of flexible substrates.
(3) The present invention, in still another aspect thereof for solving the aforementioned problem, is magnetic resonance imaging apparatus having: static magnetic field generating means for generating a static magnetic field in a space for receiving a subject to be imaged, gradient magnetic field generating means for generating a gradient magnetic field in said space, high frequency magnetic field generating means for generating a high frequency magnetic field in said space, measuring means for measuring magnetic resonance signals from said subject, and image producing means for producing an image based on said magnetic resonance signals, wherein said measuring means has an RF coil, said RF coil characterized in comprising: a base member; a pair of flexible substrates each having an electric circuit for the RF coil, one end of each flexible substrate being attached to a lateral side of said base member, the other ends of the flexible substrates being coupled to each other via a coupling member to form a cylinder; a shape defining member attached to a side of said pair of flexible substrates that corresponds to an inner side of said cylinder, for defining a curved shape of said pair of flexible substrates when said cylinder is formed; and a pair of handhold members each provided along a side that corresponds to an inner side of said shape defining member in said cylinder, each handhold member extending from one end to the other end of one of said pair of flexible substrates.
(4) The present invention, in still another aspect thereof for solving the aforementioned problem, is a magnetic resonance imaging apparatus having: static magnetic field generating means for generating a static magnetic field in a space for receiving a subject to be imaged, gradient magnetic field generating means for generating a gradient magnetic field in said space, high frequency magnetic field generating means for generating a high frequency magnetic field in said space, measuring means for measuring magnetic resonance signals from said subject, and image producing means for producing an image based on said magnetic resonance signals, wherein said measuring means has an RF coil, said RF coil characterized in comprising: a base member; a pair of flexible substrates each having an electric circuit for the RF coil, one end of each flexible substrate being attached to a lateral side of said base member, the other ends of the flexible substrates being coupled to each other via a coupling member to form a cylinder; a shape defining member attached to a side of said pair of flexible substrates that corresponds to an inner side of said cylinder, for defining a curved shape of said pair of flexible substrates when said cylinder is formed; a sheet member provided along a side that corresponds to an inner side of said shape defining member in said cylinder, extending from one end to the other end of each of said pair of flexible substrates; and a pair of handhold members each provided along a side that corresponds to an inner side of said sheet member in said cylinder, each handhold member extending from one end to the other end of one of said pair of flexible substrates.
In the invention of the aspects described regarding (1)-(4), since a pair of handhold members is provided along a side that corresponds to an inner side of the cylinder, each of which members extends from one end to the other end of one of the pair of flexible substrates, the operator can lift the hanging portion using the handhold members. Thus, the hanging portion is prevented from application of a troublesome force, and moreover, the workability is improved.
Preferably, the handhold member is an elongated flexible element with one end fixed to one end of the flexible substrate and the other end fixed to the other end of the flexible substrate, so that the lifting-up can be done easily.
Preferably, the handhold member has one end fixed to a central portion of one end of the flexible substrate and the other end fixed to a central portion of the other end of the flexible substrate, so that the lifting-up is done in good balance.
Preferably, the handhold member of the flexible element has a length greater than the length of the flexible substrate so that the hanging is not hindered.
Preferably, the handhold member is a band-like element so that the weight applied to the operator""s hand can be dispersed. Such handhold member is also preferable in that it is thin and it does not occupy a large space in the interior of the RF coil.
Preferably, the handhold member is a cord-like element so that the usage of material is reduced.
Preferably, the handhold member is a string-like element so that the usage of material is further reduced.
Preferably, the handhold member is a chain-like element so that it is stout.
Therefore, the present invention can provide an RF coil that prevents a troublesome force from arising when the hanging portion is lifted up, and a magnetic resonance imaging apparatus comprising such an RF coil. Moreover, the present invention can provide an RF coil that offers good workability for the lifting up of the hanging portion, and a magnetic resonance imaging apparatus comprising such an RF coil.
Further objects and advantages of the present invention will be apparent from the following description of the preferred embodiments of the invention as illustrated in the accompanying drawings.